Papercutter



April 2, 1968' L; D. BARLEY PAPERCUTTER 2 Sheets-Sheet 1 Filed Jan. 28,1966 INVENTOR.

LEO D. BARLEY ATTORNEYS A ril 2, 1968 L. D. BARLEY 3,375,939

PAPERCUTTER Filed Jan. 28, 1966 2 Sheets-Sheet L FIG-4 44 7-,-

United States Patent Ofiice 3,375,939 Patented Apr. 2, 1968 Filed Jan.28, 1966, Ser. No. 523,754 Claims. (Cl. 2141.6)

This invention relates to an improved back gage for use with largepapercutters, and to novel means to maintain back gage alignment and toabsorb the shocks produced when the back gage initially engages a pileof paper.

In large papercutters or trimmers, a pile of sheet material is normallyfirst placed on a work table and a movable back gage is brought intoengagement against the pile. The back gage and the pile are then movedto position the pile beneath a cutting knife where it may be clampedprior to cutting. The back gage may then move the pile forward to a newposition Where the cutting process may be repeated. Accurate cutting ofthe pile is assured only if the back gage, and particularly its facewhich engages a pile, is maintained in proper alignment with the tableand with the plane of the cutter.

Proper alignment of the back gage may readily be maintained if the backgage is kept free from any disturbing shocks or uneven sudden loadingconditions which may affect the back gage support and drive mechanism,but in modern high speed papercutters, the back gage can be moved undersome conditions at fairly high speed. Thus, should the operator cause alarge and heavy pile to be located such that the back gage engages thepile while the pile may not be centered or setting squarely on thetable, back gage alignment could be seriously affected. Not only can thealignment of the back gage with respect to the knife be affected, but,in some installations the calibration of the back gage positionindicator may be disturbed, and also the back gage control mechanism maynot thereafter track properly.

The present invention is directed to a shock absorbing device mounted onthe front face back gage to avoid misalignment of the back gage due toshocks and forces produced when the back gage engages a heavy pile ofpaper. This shock absorbing mechanism consists of a spring loaded faceplate mounted on the forward part of the back gage mechanism and adaptedto engage the pile. The springs are preloaded such that the face platewill not yield relative to the back gage due merely to the friction ofthe pile when moving the heaviest pile of paper normally encountered onthe papercutter, but which may yield when the back gage initiallyengages a heavy pile to minimize the shock on the back gage drive and topreserve alignment and to avoid damage to the drive mechanism.

A novel form of back gage drive mechanism is also provided which ismechanically more rigid and less likely to be misaligned than the priorart drive mechanisms. This drive mechanism includes a guide blockrigidly attached to the back gage and which eliminates any adjustablemechanisms between the back gage and the lead screw which were formerlyused in squaring the back gage with respect to the cutting knife.

Accordingly, it is an object of this invention to provide a shockabsorbing back gage mechanism for trimming or cutting machines, whichprotects the back gage and drive mechanism from damage and misalignmentwhen the back gage is moved into engagement with a pile of paper andwhich will remain in alignment when moving such a pile of paper acrossthe table.

It is a further object of this invention to provide a novel back gageshock absorbing mechanism which is adapted to yield when initiallyengaging a pile of paper and which may be preloaded to yield to forcessufficient to cause misalignment of the back gage but which will notyield under normal operating conditions. In addition, the back gage maybe provided with a dampening mechanism to prevent the recoil of the pileof paper after deflection of the shock absorbing mechanism.

It is a further object of this invention to provide a novel back gageshock absorbing mechanism. where the back gage will remain in alignmentwith the paper cutting table and with the plane of the cutting knifenotwithstanding the sudden engagement of the back gage with a heavy loadof paper thus to assure proper tracking of magnetic control devices andproper calibration of the back gage position indicator.

It is a further object of this invention to provide a sturdy and rigidback gage drive mechanism which is permanently aligned with the plane ofthe cutting knife and which is protected from misalignment due to shockscaused by the sudden engagement of the back gage with a pile of materialto be cut.

These and other objects and advantages of the invention will be apparentfrom the following description, the accompanying drawings and theappended claims.

In the drawings:

FIG. 1 is a side elevational view of a typical papercutter employing theshock absorbing back gage mechanism of this invention, with the sidegage partly broken away for illustration;

FIG. 2. is a pictorial view of the back gage and part of the machinetable, showing a portion of the back gage position indicating andcontrol mechanism;

FIG. 3 is a plan view of the back gage illustrating the location of theadjustable back gage supporting members;

FIG. 4 is a cross sectional view taken along line 4-4 in FIG. 3;

FIGS is a cross sectional view taken. along line 5-5 in FIG. 3;

FIG. 6 is an enlarged plan view of the left hand portion of the backgage with some of the parts broken away to show the details of itsconstruction;

FIG. 7 is a cross sectional view taken along line 77 in FIG. 6;

FIG. 8 shows one modification of the adjustable back gage supportingmembers; and

FIG. 9 shows one modification of the adjustable back gage retainingbolts.

Referring to the drawings, which show a preferred embodiment of thisinvention, and particularly to FIGS. 1 and 2, a papercutter is shownprovided with a table 10 onto which may be placed a pile of paper to becut. A back gage 12 is movable along the table and is adapted to engagethe pile of paper and push it into position under the knife 14 mountedin holder 15. Immediately prior to cutting, the paper may be heldagainst movement by clamp member 16. The extent of the sideward movementof the paper is limited by a side gage 18 mounted on both sides of thetable 10. The side gage 18 in FIG. 1 is shown partially cut away toallow a full view of the back gage.

The position of the back gage may be determined by the operator from thefront of the machine by observing the indicia on a metal tape 20 reevedon pulleys 21 and 22 and driven by the back gage through the upstandingarm 23. Power to move the back gage is supplied by a motor 27 whichrotates a lead screw 28 through a clutch mechanism generally indicatedat 29. The lead screw may also be rotated by hand from the front of themachine by turning handle 30. Surrounding the lead screw 28 and indriving engagement therewith is a driving nut 32 which is securelyattached to the back gage mechanism through a slot 33 in the table 10.

A control mechanism may also be provided to automatically position theback gage at preselected locations with respect to the cutting knife sothat a series of cuts may be made on the pile of paper. In oneapplication, the control mechanism consists of a magnetic drum 35extending along the length of the back gage above the table 10. Thismagnetic drum may have marks magnetically placed thereon which may bedetected by a pair of magnetic pickup members 36 mounted on an amplifierbox 37 secured to the back gage 12. The magnetic pic-kup heads 36 arespring biased against the magnetic drum 35 and slide along the drum tosense the position and occurrence of the magnetic control mark. Thismagnetic drum may contain more than one set of back gage positioncontrol information, and the particular set of control information inuse may be determined by rotating a selector knob 40 on the front of themachine which, through appropriate gearing, will rotate the shaft 41 andthe magnetic drum 35. A more complete description of the magneticcontrol of the back gage may be found in United States Patent 'No.3,195,385, issued July 20, 1965.

The back gage alignment with reference to the table 10 and to the planethrough which the cutting knife 14 moves must be accurately maintainedto insure that the paper will be cut properly and accurately. Inaddition, proper back gage alignment is necessary to insure accuratecalibration of the indicating tape 33' and proper tracking of themagnetic pickup heads 36 along the magnetic control drum 35. Properalignment is assured in the present invention by providing a rigid andmore rugged back gage drive mechanism and also by providing a shockabsorbing means on the paper engaging portion of the back gage to absorbthe shocks and possible unequal loading effects which may occur when theback gage initially engages a heavy pile of paper at high speed or whenthe operator slams the paper against the gage in an attempt to squarethe pile.

The back gage 12 is supported on the table 10 by a set of adjustablesupporting members 44 threaded into the opening 45 in the extendedhorizontal portion of back gage 12. These adjustable members may beformed from a metallic bolt member 46 having a wrench fitting at itsupper end and a threaded nylon portion 47 secured to the bolt 46 at theupper end and in sliding engagement with the table 10 at its lower end.A locking nut 48 is also provided to prevent rotation of the plugs oncethey are properly adjusted. A gage '50 is also permanently availableadjacent each nylon supporting member to insure proper clearance andleveling of the back gage 12 with respect to table 10. This gagecomprises a metallic depth pin 50 having a length accurately determinedso that the upper surface 51 of the pin will be flush with the adjacentsurface of the back gage 12 when the pin is in engagement with the table10 and the proper clearance of about .003 inch, indicated at 52, existsbetween the lowermost portion of the back gage 12 and the table 10.

An alternative embodiment of the back gage supporting member 44' isshown in FIG. 8. In this embodiment a nylon plug 55 is inserted into theopening 45 in the back gage and a threaded metallic adjustment screw 56is threaded through the upper portion of the back gage. The screw '56 isalso provided with an opening 57 adapted to receive an Allen wrenchwhile a locking nut 58 prevents rotation once the plug is properlyadjusted.

The back gage drive mechanism includes a back gage guide block 60positioned beneath the table 10 and in 4 driving engagement .with thelead screw 28. As shown in FIG. 4, a boss extends from the guide block60 and includes the driving nut 32 which is securely held in position bythe clamping bolt 61. A ta-per pin 62 is also provided to preventrotation of the nut 32.

The table 10 is provided with a downwardly projecting tongue member 65having a machined surface 66 accurately finished square to the plane ofthe cutting knife 14. In addition, the tongue 65 has a portion 67machined to be parallel with the surface 66 and therefore also square tothe plane of the cutting knife. The surface 70 of the guide block 60 isalso finished flat so that it is in sliding engagement with the surface66 on the tongue 65. A gib 71 engages the surface 67 on the tongue andmay be adjustably pressed against the surface by several bolts 72, onlyone of which is shown in FIG. 4. A depression in the gib 67 under eachbolt 72 serves to keep the gib from sliding with respect to the guideblock 60. Thus, the back gage guide block 60 is guided by the tongueportion 65 on the table 10 and insures that the guide block 60 willremain square to the plane of the cutting knife 14 throughout its lengthof travel.

A portion 74 of the guide block 60 extends upwardly through the slot 33in the table 10 into the keyway 75 defined in the downwardly extendingprojections 76 on the back gage 12. A pair of bolts 77 extend throughthe back gage 12 and into the guide block 60 to hold these two membersin clamping engagement. The back gage therefore is securely mounted tothe guide block 60 and keyway 75 will remain square with the plane ofthe cutting knife 14.

Shims may be positioned between the upper surface of the upwardlyextending portion 74 of the guide block 60 and the keyway 75 in theguide block. In addition, an adjustment, which may include gib blocks 78and a set of adjusting screws 79, may be provided between the lowermostportion of the tongue 65 and the guide block 74. The inclusion of thesemodifications will in large part be dictated by the tolerances specifiedin machining the various component par-ts of the drive and guidemechanism.

With the main portion of the back gage 12 therefore aligned with theplane of the cutting knife 14 and with the table 10, proper tracking ofthe magnetic pickup heads 36 along the magnetic drum 35 is thus assuredas well as the accuracy of the tape indicator 20. In the prior art papercutting devices using an adjustable coupling means between the drivemechanism and the back gage, misalignment was possible which could causefailure of the magnetic pickup heads to sense the control marks due toexcessive spacing as well as misalignment of the back gage positionindicator. With the drive mechanism herein described, however, theseproblems are eliminated.

Protection of the back gage and the back gage driving mechanism fromuneven loading and sudden forces due to the engagement of the back gagewith a heavy pile of paper may be provided by the shock absorbingmechanism shown particularly in FIGS. 6 and 7. The shock absorbingmechanism comprises a yielding face plate 80 having a front portionadapted to engage a pile of papers 81. The back gage 12 has an L-shapedthroat portion 82 at its forward part provided with a sliding surface 83adapted to be in sliding engagement with the inwardly extending member84 of the plate 80. A set of springs 86 are positioned between the plate80 and the upstanding portion 82 of the back gage and are maintained incompression by a set of bolts 88. In the preferred embodiment of thisinvention four pairs of coil springs 86 are evenly spaced across theback gage between the paper engaging plate 80 and the portion 82 on theback gage.

As shown in FIG. 5, the bolt 88 extends through a boss 89 on the faceplate 80 and may be secured in place by a locking nut 90. An extendedportion of the bolt extends through the upstanding portion 82 of theback gate 12 and has threaded onto its end an adjusting nut 91 andlocking nut 92. The bolts 88 are adjusted to preload the springs 86 sothat they will not be deflected by the normal frictional forces whichmust be overcome in order to move the heaviest pile of paper 81 acrossthe table into position under the knife 14 and clamp 17. On the otherhand, the springs are adjusted so that they may yield and absorb theshocks created when the back gage is moved initially against a pile ofpaper 81. Suflicient clearance is provided between the plate 80 and theback gage to prevent actual contact of these two members. The amount ofclearance is dictated by the stiffness and the number of the springs 86.

To prevent a recoil of the pile of paper 81 away from the plate 80 whenthe back gage is initially moved against the pile, a dampening mechanism95 is provided which allows the plate 80 to move toward the back gagefreely, being restrained only by the springs 86, but which will causethe plate slowly to return to its normal position as determined by theposition of the nut 91 at such a rate that the paper will not be thrownaway from the face plate 80. Since it is common in some paper cutters tohave an air bearing between the pile of paper 81 and the table 10, sucha recoil could impede the smooth and speedy operation of the machine.

As shown in FIG. 3, the center bolt 88 is normally used to preload thesprings to the desired degree while the bolts 88 at each end may be usedto make minor adjustments in the alignment of the plate 80 with respectto the plane of the cutting knife 14 and thereby achieve absoluteparallelism.

One modification of the bolt means used to limit the travel of plate 80with respect to the upstanding member 82 on the back gage and to preloadthe springs 86 is shown in FIG. 9. A stud member 96 is threaded into theboss 89, and a bolt 97 extends through the front surface of the plate 80and is threaded in the stud 96. A hexagonal portion 98 facilitatesassembly by providing a wrench engaging surface. An adjusting nut 91 anda locking nut 92 are placed on the portion of the stud extending throughmember 82.

A shock absorbing back gage has therefore been described which is usefulespecially on large scale paper cutters and which is provided with aguide block and drive mechanism especially adapted to hold the back gagein alignment with the plane of the cutting knife and which includes ashock absorbing face plate on the back gage to absorb any shocks whichmay be transmitted through the back gage to the drive mechanism andwhich would otherwise tend to create a misalignment or damage to themachine.

While the form of apparatus herein described constitutes a preferredembodiment of the invention, it is to be understood that the inventionis not limited to this precise form of apparatus, and that changes maybe made therein without departing from the scope of the invention whichis defined in the appended claims.

What is claimed is:

1. A cutting apparatus comprising a table for supporting a pile of sheetmaterial to be cut, cutting means mounted above said table, a back gagemovable on said table and adapted to position said pile under saidcutting means, drive means mounted beneath said table for moving saidback gage, said table being provided with a slot in the direction of theback gage movement, guide block means extending through said slot andfixed to said back gage, cooperating means on said table in slidingengagement with said guide block means for maintaining said back gage inalignment with said table, said guide block means further being indriving engagement with said drive means for movement of said back gage,and yielding means mounted on the forward portion of said back gage fordeflecting and absorbing the impact when the back gage is initiallyengaged with a pile and which will remain undeflected when said pile isbeing moved normally across the table.

2. The apparatus as defined in claim 1 wherein said yielding meansincludes a plate adapted to engage said pile, spring means positionedbetween said plate and the forward portion of said back gage, and meansto preload said spring means so that the plate will not be deflectedrelative to said back gage when a pile is being moved normally by saidback gage but which may deflect and absorb the impact when the back gageis. initially engaged with said pile thereby to minimize the shockstransmitted to the back gage and associated drive means.

3. The apparatus as defined in claim 2 wherein said means to preloadsaid spring means includes a bolt member attached to said plate andextending through a portion of said back gage and arranged to place saidspring means in compression thereby requiring a force exceeding theamount of the preloading to cause further compression of said springmeans and consequent yielding of said plate.

4. The apparatus as defined in claim 1 wherein said back gage comprisesa horizontal member provided with a plurality of adjustable supportmeans in sliding engagement with said table for determining theclearance between the back gage and the table, a throat portion at theforward part of said back gage, a plate mounted for limited movement insaid throat portion adapted to engage said pile, a plurality of springspositioned between said plate and said throat portion, and adjustablemeans to preload said springs so that said plate will yield to forceswhich exceed that required to move the heaviest anticipated pile ofsheet material.

5. The apparatus as defined in claim 1 wherein said yielding meansincludes a plate having a forward portion adapted to engage said pile, athroat portion at the forward part of the back gage adapted to receivein sliding engagement a portion of said plate, spring means positionedbetween said plate and said throat portion, and means to preload saidspring means so that said plate will yield to forces which exceed thatrequired to move the heaviest pile across said table, and dampeningmeans positioned between said plate and said throat portion forrestraining the rapid return of the plate to its normal position afterbeing deflected by the engagement of a pile while permittingunrestrained compression of said springs during initial deflection ofsaid plate.

6. The apparatus as defined in claim 1 wherein said yielding meansincludes a plate having a front portion adapted to engage said pile,spring means positioned between said plate and the forward portion ofsaid back gage, means to preload said spring means such that the platewill not be deflected relative to said back gage when a pile is beingmoved normally by said. back gage but which may deflect and absorb theimpact when the back gage is initially engaged with said pile thereby tominimize the shocks transmitted to the back gage and the associateddrive means, and adjusting means for aligning said plate parallel to theplane of said cutting means.

7. The apparatus as defined in claim 6 wherein said means to preloadsaid spring means includes a first bolt member attached to said plateand extending through a portion of said back gage and arranged to placesaid spring means in compression thereby requiring a force exceeding theamount of the preloading to cause further compression of said springmeans and consequent yielding of said plate, and at least one other boltmember attached to said plate and extending through a portion of saidback gage at a position remote from said first bolt member andadjustable to align the pile engaging portion of said plate parallel tothe plane of said cutting means.

8. The apparatus as defined in claim 6 wherein said adjusting meansincludes a pair of bolt members attached to said plate at substantiallyeach end thereof, said bolt members extending through a portion of saidback gage and adjustable to align the pile engaging portion of saidplate parallel to the plane of said cutting means.

9. The apparatus as defined in claim 1 wherein said back gage comprisesa horizontal member provided with a throat portion at the forward partthereof, a plate mounted for limited movement in said throat portionadapted to engage said pile, a plurality of springs positioned betweensaid pile and said throat portion, adjustable means to preload saidsprings such that the plate Will yield to forces Which exceed thatrequired to move the heaviest anticipated pile, and adjusting meansattached to said plate to align the pile engaging portion of said plateparallel to the plane of said cutting means.

10. The apparatus as defined in claim 9 wherein said adjusting meansincludes a bolt member attached to said '8 plate at substantially eachend thereof, said bolt members each extending through Said throatportion of said back gage and adjustable to align the pile engagingportion of said plate parallel to the plane of said cutting means.

References Cited UNITED STATES PATENTS 3,032,209 5/1962 Mead 214l.6

GERALD M. FORLENZA, Primary Examiner.

F. E. WERNER, Assistant Examiner.

1. A CUTTING APPARATUS COMPRISING A TABLE FOR SUPPORTING A PILE OF SHEETMATERIAL TO BE CUT, CUTTING MEANS MOUNTED ABOVE SAID TABLE, A BACK GAGEMOVABLE ON SAID TABLE AND ADAPTED TO POSITION SAID PILE UNDER SAIDCUTTING MEANS, DRIVE MEANS MOUNTED BENEATH SAID TABLE FOR MOVING SAIDBACK GAGE, SAID TABLE BEING PROVIDED WITH A SLOT IN THE DIRECTION OF THEBACK GAGE MOVEMENT, GUIDE BLOCK MEANS EXTENDING THROUGH SAID SLOT ANDFIXED TO SAID BACK GAGE, COOPERATING MEANS ON SAID TABLE IN SLIDINGENGAGEMENT WITH SAID GUIDE BLOCK MEANS FOR MAINTAINING SAID BACK GAGE INALIGNMENT WITH SAID TABLE, SAID GUIDE BLOCK MEANS FURTHER BEING INDRIVING ENGAGEMENT WITH SAID DRIVE MEANS FOR MOVEMENT OF SAID BACK GAGE,AND YIELDING MEANS MOUNTED ON THE FORWARD PORTION OF SAID BACK GAGE FORDEFLECTING AND ABSORBING THE IMPACT WHEN THE BACK GAGE IS INITIALLYENGAGED WITH A PILE AND WHICH WILL REMAIN UNDEFLECTED WHEN SAID PILE ISBEING MOVED NORMALLY ACROSS THE TABLE.